Rude supervisors and degrading business

Have any of you experienced the poor customer service this company has? I have been with Sprint for 20 years and recently, even though I was not told, I was migrated to T-Mobile. Worst cell provider ever. I upgraded 2 phones and added 2 lines back in July of last year. I was quoted a flat bill rate of $230 a month. I have been paying over $330 every month since. I finally spoke to a wonderful customer service supervisor and she was supposed to credit my account back $890 that I over paid within 24 hours. This did not happen. She tried but higher up people denied it, even though she gave me a active transaction number to use for the refund to my bank account and all. So when the payment didn't arrive, I called and spoke to another supervisor. She was extremely rude and told me she knew where I upgraded and purchased my phones. She said it was a Sprint by T Mobile store. Never ever has any TMobile store on Omaha, NE or CB, IA ever had a sign stating Sprint by TMobile. The store reps were on the phone with them for countless hours and could never get anywhere. Needless to say, if you look online, they are all TMobile stores therefore, false advertisement and the supervisor even told me she agreed but nothing she could do. The service is horrible, the phones cut in and out all the time. When an app asks for your current location it places me in colorado which is over 8 hours away from me. Needless to say, the scammed me out of $890 and now my business is going to drop them for all services also. This is fraudulant and they cannot say one thing and do another. Finally my bill had been corrected. Then this new supervisor gets on and starts in with her lecture. Are we supposed to receive letters stating that TMobile is now taking over Sprint over a year ago and then to find out you have spoken to Tmobile reps numerous times and they have never claimed to be sprint. Now they are telling me I have to call Sprint to get a refund???? What the heck??? I thought the company purchased Sprint??? Why is this my responsibility. I am livid and now searching for a new phone carrier for the business and my personal 4 lines along with the rest of my family leaving and going elsewhere. I am ashamed that Sprint combined with such a negligent company. And they train their employees to be negligent as well. I will not let this drop until corporate reaches out and I want the girl I spoke with on 6/5/23, she needs verbal coaching and classes on customer service. I am a Hospice nurse and I would never allow employees to talk to patients or families that way. What a shame this is. TMobile is by far the worst cell company ever.